Interpretation please "Old War"

I found a necessary entry in "Index to War of 1812 Pension Files" Vol II: J-Z.transcribed by Virgil D. White The entry is from widow's file, but it includes the term "Old War".A number of other entries under the family name sought also refer to "Old War".Since my military history is "there was a battle and we won", I would appreciate a detailed explanation of this term.Please.